1. Field
Embodiments of the invention relate to the field of mechanical couplers; and more specifically, to couplers for transferring control motion from robotic manipulators.
2. Background
Minimally invasive medical techniques have been used to reduce the amount of extraneous tissue which may be damaged during diagnostic or surgical procedures, thereby reducing patient recovery time, discomfort, and deleterious side effects. Traditional forms of minimally invasive surgery include endoscopy. One of the more common forms of endoscopy is laparoscopy, which is minimally invasive inspection or surgery within the abdominal cavity. In traditional laparoscopic surgery, a patient's abdominal cavity is insufflated with gas and cannula sleeves are passed through small (approximately ½-inch) incisions in the musculature of the patient's abdomen to provide entry ports through which laparoscopic surgical instruments can be passed in a sealed fashion.
The laparoscopic surgical instruments generally include a laparoscope for viewing the surgical field and working tools defining end effectors. Typical surgical end effectors include clamps, graspers, scissors, staplers, and needle holders, for example. The working tools are similar to those used in conventional (open) surgery, except that the working end or end effector of each tool is separated from its handle by an approximately 12-inch long extension tube, for example, so as to permit the operator to introduce the end effector to the surgical site and to control movement of the end effector relative to the surgical site from outside a patient's body.
In order to provide improved control of the working tools, it may be desirable to control the instrument with a robotic manipulator. The surgeon may operate controls on a console to indirectly manipulate the instrument that is connected to the robotic manipulator. The instrument is detachably coupled to the robotic manipulator so that the instrument can be separately sterilized and selected for use as needed instrument for the surgical procedure to be performed. The instrument may be changed during the course of a surgery.
It is desirable to provide a close coupling between the surgeon's hand movement and the associated instrument movement. Therefore, it is desirable to provide a mechanism for transmitting to controlling motions of a robotic manipulator to a detachable laparoscopic surgical instrument without lost motion or hysteresis.